Fabrication tolerant high-speed SiP ring modulators and optical add-drop multiplexers for WDM applications

Silicon ring resonator modulators (RRMs) have great potential to reduce footprint and power consumption and to increase modulation speeds in wavelength division multiplexed (WDM) transmitters. However, the optical properties of RRMs are highly sensitive to fabrication variations, which makes them challenging to design for volume production or a large number of WDM-channels. In this work, we present an RRM design that was specifically designed and experimentally validated to have reduced sensitivity to fabrication variations. This includes a sensitivity analysis of resist over- and under-exposure (±30 nm lateral dimension deviation) and of etch depth variability (±10 nm depth variation) within the coupling section. For our design, the deviation from the targeted coupling strength is improved twofold. The proposed devices are fabricated on SOI wafers using a standard CMOS-compatible process. We demonstrate RRMs with an extinction ratio above 5 dB, an OMA better that -7 dB (at 2 Vpp) and a 29 GHz electro-optical bandwidth, showing open eye diagrams at 32 Gb/s limited only by our measurement setup. The measured coupling coefficients are in good agreement with the simulated values. Furthermore, we applied the same design modifications to realize low-doped RRMs as well as ring based adddrop-multiplexers (OADMs). The agreement between the simulated and the measured coupling coefficients (that we identified as the main source of device performance variability) further confirms the effectiveness of our design modifications. These results suggest that the proposed design can be exploited to enable reliable fabrication of resonantbased devices on a large scale, especially in WDM systems

Polarization-diverse silicon photonics WDM receiver with a reduced number of OADMs and balanced group delays

We experimentally validate a 10-channel polarization diverse WDM receiver with only one ring based add-drop multiplexer per channel and on-chip optical delay lines balancing the two polarization paths for speeds up to 28 Gb/s

Reconfigurable Frequency-Selective Resonance Splitting in Chalcogenide Microring Resonators

This paper reports a method to enable, for the first time, reconfigurable control of resonance splitting of one or multiple arbitrarily selected azimuthal orders in a microring resonator. This is accomplished by inscribing Bragg gratings in photosensitive Ge23Sb7S70 chalcogenide microring resonators via a novel cavity-enhanced photoinscription process, in which injection of light at the targeted C-band resonance frequency induces a spatially varying refractive index change. The so formed Bragg grating precisely matches the selected resonance order without introducing optical losses. Long-term room temperature stability of the photoinscribed Bragg gratings has been verified in darkness and during operation with reduced optical power levels. The Bragg gratings can be reconfigured by first erasure with flood illumination of visible light at 561 nm and subsequent reinscription. We also report controlled splitting of multiple resonances by inscribing superimposed Bragg gratings